Answer:
-a^2 - a + 12
Step-by-step explanation:
You only need to find the products of the first and last terms to determine the correct answer:
(-a)(a) = -a^2
(3)(4) = 12
You're looking for an expression with -1 as the leading coefficient and +12 as the constant. There is only one choice like that:
-a^2 - a + 12
